Abstract
Responses of phytoplankton biomass were monitored in pelagic enclosures subjected to manipulations with nutrients (+N/P), planktivore roach (Rutilus rutilus) and large grazers (Daphnia) in 18 bags during spring, summer and autumn in mesotrophic Lake Gjersjøen. In general, the seasonal effects on phytoplankton biomass were more marked than the effects of biomanipulation. Primary top-down effects of fish on zooplankton were conspicuous in all bags, whereas control of phytoplankton growth by grazing was observed only in the nutrient-limited summer situation. The effect of nutrient additions was pronounced in summer, less in spring and autumn; additions of fish gave the most pronounced effect in spring. The phytoplankton/zooplankton biomass ratio remained high (10–100) in bags with fish, with the highest ratios in combination with fertilization. The ratio decreased in bags without fish to<2 in most bags, but a real grazing control was only observed in bags with addition ofDaphnia. No direct grazing effects could be observed on the absolute or relative biomass of cyanobacteria (mainlyOscillatoria agardhii). The share of cyanobacteria in total phytoplankton biomass was lowest in summer (7–26%), higher in spring (39–63%) and more than 90% in the autumn experiment. The development of the cyanobacterial biomass was rather synchronous in all bags in all the three experiments. A high biomass ofDaphnia gave no increase in the pool of dissolved nutrients in spring, a slight increase in summer and a pronounced increase in autumn. While a strong decrease in the P/C-cell quota of the phytoplankton was observed from spring to autumn, no effect of grazing or nutrient release could be related to this P/C-status. The experiments indicate that such systems, with high and stable densities of inedible cyanobacteria, are rather insensitive to short-term (3–4 weeks) biomanipulation efforts. This is supported by observations on the long-term development of the lake.
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References
Anderson, G., H. Berggren, G. Cronberg & C. I. Gelin, 1978. Effects of planktivorous fish on organisms and water chemistry in eutrophic lakes. Hydrobiologia 59: 9–15.
Bottrell, H. H., A. Duncan, Z. A. Gliwicz, E. Grygierek, A. Herzig, A. Hillbricht-Ilkowska, H. Kurasawa, P. Larsson & T. A. Weglenska, 1976. A review on some problems in zooplankton production studies. Norw. J. Zool. 24: 419–456.
Brabrand, Å, B. A. Faafeng & J. P. Nilssen, 1986. Juvenile roach and invertebrate predators: delaying the recovery phase of eutrophic lakes by suppression of efficient filter-feeders. J. Fish Biol. 29: 99–106.
Brabrand, Å, B. A. Faafeng & J. P. Nilssen, 1987. Pelagic predators and interfering algae: Stabilizing factors in temperate eutrophic lakes. Arch. Hydrobiol. 110: 533–552.
Brabrand, Å., B. A. Faafeng & J. P. Nilssen, 1990. Relative importance of phosphorus supply to phytoplankton production: fish excretion versus external loading. Can. J. Fish. aquat. Sci. 47: 364–372.
Carpenter, S. R. & J. F. Kitchell, 1988. Consumer control of lake productivity. BioScience 38: 764–769.
Carpenter, S. R., J. F. Kitchell & J. R. Hodgson, 1985. Cascading trophic interactions and lake productivity. BioScience 35: 634–639.
Dawidowicz, P., Z. M. Gliwicz & R. D. Gulati, 1988. CanDaphnia prevent a blue-green algal bloom in hypertrophic lakes? A laboratory test. Limnologica (Berlin) 19: 21–26.
Faafeng, B. & J. P. Nilssen, 1981. A twenty year study of eutrophication in a deep soft-water lake. Verh. int. Ver. Limnol. 20: 214–224.
Gliwicz, Z. M, 1990. Why do cladocerans fail to control algal blooms? Hydrobiologia, 200/201: 83–97.
Henderson-Sellers, B. & H. R. Markland, 1987. Decaying lakes: the origin and control of cultural eutrophication. John Wiley & Sons, U.K., 254 pp.
Hessen, D. O. & J. P. Nilssen, 1985. From phytoplankton to detritus and bacteria: effects of short-term nutrient and fish perturbations in an eutrophic lake. Arch. Hydrobiol. 105: 273–284.
Hessen, D. O., 1989. Factors determining the nutritive status and production of zooplankton in a humic lake. J. Plankton Res. 11: 649–664.
Lampert, W., 1987. Feeding and nutrition inDaphnia. In: Peters, R. H. & R. DeBernardi: Daphnia. Mem. Ist. Ital. Idrobiol. Dott. March. 45: 143–192.
Lyche, A., B. A. Faafeng & Å. Brabrand, 1990. Predictability and possible mechanisms of plankton response to reduction of planktivorous fish. Hydrobiologia, 200/201: 251–261.
McQueen, D. J. & J. R. Post, 1988. Cascading trophic interactions: Uncoupling at the zooplankton-phytoplankton link. Hydrobiologia 159: 277–296.
Nilssen, J. P. 1978. Eutrophication, minute algae and inefficient grazers. Mem. Ist. ital. Idrobiol. 36: 121–138.
Olsen, Y., 1984. Estimering av algebiomasse i naturlige algesamfunn. Limnos 3/84: 1–12 (in Norwegian).
Olsen, Y., Jensen, A., Reinertsen, H. & B. Rugstad, 1983. Comparison of different algal carbon estimates by use of the Droop-model for nutrient limited growth. J. Plankton Res. 5: 43–51.
Sas, H., 1989. Lake restoration by reduction of nutrient loading: expectations, experiences, extrapolations/coordination. Academia Verlag.
Shapiro, J., B. Forsberg, G. Lamarra, M. Lindmark, M. Lynch, E. Smeltzer & G. Zoto, 1982. Experiments and experiences in biomanipulation-studies of biological ways to reduce algal abundance and eliminate blue-greens. EPA-600/3-82-096. Corvallis Environ. Res. Lab. US. EPA, Corvallis, Oregon, USA, 251 pp.
Sommer, U., M. Gliwicz, W. Lampert & A. Duncan, 1986. The PEG-model of seasonal succession of planktonic events in freshwaters. Arch. Hydrobiol. 106: 433–471.
Vanni, M. J., 1987. Effects of food availability and fish predation on a zooplankton community. Ecol. Monogr. 57: 61–88.
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Faafeng, B.A., Hessen, D.O., Brabrand, Å. et al. Biomanipulation and food-web dynamics — the importance of seasonal stability. Hydrobiologia 200, 119–128 (1990). https://doi.org/10.1007/BF02530333
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DOI: https://doi.org/10.1007/BF02530333